1. Technical Field
The described embodiments pertain to interpreting location data and other data about a person collected from mobile devices and internetworked services.
2. Description of Related Art
Many mobile devices now have the capability of recording location and other information. Having a complete record of when and where the user goes is useful for a variety of applications, including recommendation systems, lifelogging, and goal tracking. However, there are a number of obstacles to building useful applications on top of the kinds of data streams currently available.
First, these data streams are noisy, imprecise, and sometimes unavailable. Global Positioning System (GPS) technology, for example, can be confused by surrounding buildings or other features and is not available indoors. Cell tower triangulation is imprecise, while also unavailable where there are no cell towers. WiFi triangulation is error-prone and also unavailable in the absence of nearby WiFi networks.
Second, sensor readings such as taking satellite or radio readings can cause a significant drain on the device's battery, so they must be done sparingly. Naturally, this increases the uncertainty in the data, with large gaps from one reading to the next.
Third, location data in the form of latitude/longitude readings has no semantic content and is useless for many applications. Because of the noisy nature of the data, translating lat/long into addresses or named locations is difficult, especially in the dense urban areas where most users live.